Residual joint displacement monitoring and compensation

Abstract

An apparatus for manipulation and evaluation of a joint includes a frame to support the joint and to facilitate an application of force away from the joint for the evaluation of the joint, a bracket assembly supported by, and moveable relative to, the frame, the bracket assembly being configured to engage the joint, and a sensor coupled to the bracket assembly such that the sensor is moved by displacement of the bracket assembly relative to the frame during the evaluation of the joint, the sensor being configured to generate a signal indicative of the displacement.

What is claimed is: 
     
       1. An apparatus for manipulation and evaluation of a joint, the apparatus comprising:
 a frame to support the joint; 
 a drive supported by the frame, the drive being configured to manipulate, in a first direction, a bone connected to the joint during the evaluation of the joint; 
 a clamp supported by the frame, the clamp being configured to stabilize a part of the joint during the evaluation of the joint; 
 a bracket assembly carried by the clamp, the bracket assembly being configured to engage the joint, the bracket assembly being moveable relative to the clamp in a second direction different than the first direction; and 
 a sensor coupled to the bracket assembly such that the sensor is moved by displacement of the bracket assembly relative to the clamp in the second direction during the evaluation of the joint, the sensor being configured to generate a signal indicative of the displacement; 
 wherein the displacement is indicative of movement of the part of the joint stabilized by the clamp, the movement being in the second direction. 
 
     
     
       2. The apparatus of  claim 1 , wherein respective ends of the bracket assembly engage medial and lateral sides of the joint. 
     
     
       3. The apparatus of  claim 1 , wherein the displacement comprises medial-lateral translation. 
     
     
       4. The apparatus of  claim 1 , wherein:
 the joint includes a first bone and a second bone; 
 the first bone is the bone manipulated by the drive; 
 the clamp is configured to stabilize the second bone; and 
 the displacement is indicative of residual movement of the second bone during the joint evaluation. 
 
     
     
       5. The apparatus of  claim 4 , further comprising a processor configured to adjust position data for the first bone in accordance with data indicative of the displacement to compensate for the residual movement of the stabilized part of the joint during the joint evaluation. 
     
     
       6. The apparatus of  claim 1 , further comprising a linear bearing mounted on the frame, wherein:
 the bracket assembly comprises a bar disposed in the linear bearing; and 
 the sensor is mounted on the bar such that the displacement includes translation of the bar within the linear bearing. 
 
     
     
       7. The apparatus of  claim 6 , further comprising a rod attached to the sensor, wherein:
 the rod extends from the sensor to establish a contact point with the joint; and 
 the sensor is slidably coupled to the bar to allow displacement of the rod and the sensor as a result of movement of the joint in a direction other than a direction of the translation. 
 
     
     
       8. The apparatus of  claim 6 , wherein the bracket assembly comprises:
 a pair of link posts extending from the bar to position respective ends of the bracket assembly along opposite sides of the joint; 
 a pair of arms, each arm of the pair of arms extending laterally inward from a respective link post of the pair of link posts toward a respective side of the opposite sides of the joint; and 
 a pair of pads, each pad of the pair of pads disposed on a respective side of the opposite sides of the joint. 
 
     
     
       9. The apparatus of  claim 8 , wherein connections between the pair of arms and the pair of link posts are adjustable to modify a spacing between the pair of pads. 
     
     
       10. The apparatus of  claim 6 , wherein the translation of the bar is indicative of the movement of the part of the joint stabilized by the clamp. 
     
     
       11. The apparatus of  claim 6 , wherein the translation of the bar is in the second direction. 
     
     
       12. The apparatus of  claim 1 , wherein the bracket assembly comprises a pair of link posts configured to position respective ends of the bracket assembly along opposite sides of the joint such that the pair of link posts and the respective ends are moved in the second direction during the displacement of the bracket assembly. 
     
     
       13. The apparatus of  claim 1 , wherein the bracket assembly comprises a pair of arms extending laterally inward toward opposite sides of the joint such that the pair of arms are moved in the second direction during the displacement of the bracket assembly. 
     
     
       14. The apparatus of  claim 1 , wherein the bracket assembly comprises a pair of pads disposed on opposite sides of the joint such that the pair of pads are moved in the second direction during the displacement of the bracket assembly.